Note
This section describes the mechanical functions of the system
components and emphasizes the importance of following the correct
procedures to avoid unnecessary circuit card failures. This section is
for background information only. Refer to the section "
Removing and
Replacing a Trunk Card
" for specific procedures regarding the CT1
and CE1 trunk card.
Each dial shelf controller card and feature card contains a female
connector with which it connects to a male connector on the system
backplane. Each male backplane connector comprises a set of tiered
pins, in two lengths. The backplane pins send specific signals to the
system as they make contact with the card connectors. The system
assesses the signals it receives and the order in which it receives them
to determine what event is occurring and what task it needs to perform,
such as reinitializing new interfaces or shutting down removed ones.
Each dial shelf controller card and feature card is designed with two
ejector levers to be used when you install or remove a card (see ). The
function of the ejector levers is to align and securely seat the card
connectors in the backplane.
Caution
Do not force the dial shelf controller cards or feature cards into a slot, as this
can damage the backplane connector pins if they are not aligned
properly with the card connectors.
Note
To avoid erroneous failure messages, you must allow at least
15 seconds for the system to reinitialize and note current interface
configurations before you remove or insert a dial shelf controller card
or feature card in the dial shelf.
Safety Guidelines
This section provides safety and ESDprevention guidelines to help
you avoid injury to yourself and avoid damage to the equipment. The
following safety guidelines are recommended when working with any
equipment that connects to electrical power or telephone wiring:
•
Locate the emergency poweroff switch for the room in which you
are working before beginning any procedures requiring access to
the chassis interior.
•
Never work alone when potentially hazardous conditions exist.
•
Never assume that power has been disconnected from a circuit;
always check.
•
Never perform any action that creates a potential hazard to people
or makes the equipment unsafe.
•
Carefully examine your work area for possible hazards such as
moist floors, ungrounded power extension cables, and missing
safety grounds.
•
This unit is to be installed in a restricted access area in
accordance with articles 11016, 11017, and 11018 of the
National Electric Code, ANSI/NFPA 70.
Telephone Wiring Guidelines
The following guidelines are recommended when working with any
equipment that is connected to telephone wiring or to other network
cabling:
•
Never install telephone wiring during a lightning storm.
•
Never install telephone jacks in wet locations unless the jack is
specifically designed for wet locations.
•
Never touch uninsulated telephone wires or terminals unless the
telephone line has been disconnected at the network interface.
•
Always use caution when installing or modifying telephone lines.
Preventing Electrostatic Discharge Damage
Electrostatic discharge (ESD) damages equipment and impairs
electrical circuitry. ESD occurs when printed circuit cards are
improperly handled and results in complete or intermittent failures.
The system feature cards and dial shelf controller cards consist of a
printed circuit board that is fixed in a metal carrier. Electromagnetic
interference (EMI) shielding, connectors, and ejector levers are integral
components of the carrier. Handle the cards by their carrier edges or
ejector levers only; never touch the printed circuitry, card components,
or connector pins.
Although the metal carrier helps to protect the printed circuitry from
ESD, you should wear a preventive antistatic strap whenever handling
feature cards or dial shelf controller cards. Ensure that the strap makes
